THESIS
2008
xxii, 155 p. : ill. (some col.) ; 30 cm
Abstract
Calcium phosphate and fluoridated calcium phosphate thin films were successfully deposited on acid etched pure titanium substrates by the electrochemical deposition method. A nano-thickness (around 200 nm) thin film was obtained by controlling the current density, reaction duration and other electrochemical reaction parameters. The thin films were dense and uniform. The Ca/P atomic ratio of the electrochemical deposition thin film gradually increased with the rise of the fluorine atomic concentration. Even under the same experiment condition, the thickness of the thin film deposited in Electrolyte C was obviously larger than that of the thin films deposited in Electrolyte A and B. It is reasonable to consider that the electrochemical deposition rate will increase when the fluorine atomi...[
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Calcium phosphate and fluoridated calcium phosphate thin films were successfully deposited on acid etched pure titanium substrates by the electrochemical deposition method. A nano-thickness (around 200 nm) thin film was obtained by controlling the current density, reaction duration and other electrochemical reaction parameters. The thin films were dense and uniform. The Ca/P atomic ratio of the electrochemical deposition thin film gradually increased with the rise of the fluorine atomic concentration. Even under the same experiment condition, the thickness of the thin film deposited in Electrolyte C was obviously larger than that of the thin films deposited in Electrolyte A and B. It is reasonable to consider that the electrochemical deposition rate will increase when the fluorine atomic concentration of the electrolyte has been increased.
The as-prepared amorphous calcium phosphate and fluoridated calcium phosphate thin films were successfully transformed to hydroxyapatite (HA) and fluoridated hydroxyapatite (FHA) respectively, using a 600℃ heat treatment with water vapor for 3 hours. SEM, TEM and EDS were employed to systematically characterize the thin film after the heat treatment. Combining the single crystal diffraction (SAD) and the energy dispersive spectroscopy (EDS) techniques, we successfully identified HA and FHA. High quality and clear HRTEM pictures also confirmed the phase identification results came from the single crystal diffraction pattern. Combining the crystal structure and chemical information obtained from the same thin film sample which was electrochemically deposited in the electrolyte which contained fluorine and heat treated in a humid atmosphere, we concluded that the fluorine ions entered the crystal lattice of HA to substitute the hydroxyls.
We successfully demonstrate that the FHA has antibacterial activity compared with HA and pure Ti as control. S.aureus and E.coli as the Gram-positive and Gram-negative bacteria respectively were used in this study. So we conclude that the FHA could be effective in inhibiting the growth and proliferation of both Gram-positive and Gram-negative bacteria.
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